I’m a huge fan of apps like iA Writer and Taskpaper: they let you truly focus on what you’re doing, and everything else just goes away. I like to employ a similar approach to design: eliminate all distractions and immerse yourself in what you’re working on. Here’s what it looks like:
With Photoshop CS6, it’s easier to create a ‘focus mode’ than it has ever been. I use a 27″ iMac and (LED / Thunderbolt) Cinema Displays for work, so with its darkest UI color, dock auto-hiding (don’t forget to eliminate that annoying pop-up delay) and Nocturne (a utility that darkens your menubar and even dims / hides it if your mouse isn’t over it) you can completely focus on your design process, unhindered by any distractions. The UI that’s there simply blends into the black bezel of your hardware.
You can also keep your reference windows (say, your browser or editor) open on a secondary screen. Voilà: true focus. Good music mandatory.